Basic-region leucine zipper (bZIP) proteins are one of the largest transcription factor families that regulate a wide range of cellular functions. Owing to the stability of their coiled coil structure leucine zipper (LZ) domains of bZIP factors are widely employed as dimerization motifs in protein engineering studies. In the course of one such study, the X-ray structure of the retro-version of ...

To explore the role of the HLH subdomain in bHLHZ proteins, we designed sets of minimalist proteins based on bHLHZ protein Max, bHLH/PAS protein Arnt and bZIP protein C/EBP. In the first, the Max bHLH and C/EBP leucine zipper were fused such that the leucine heptad repeats were not in register; therefore, the protein dimerization interface was disrupted. Max1bHLH-C/EBP showed little ability to ...

BACKGROUND The transcription factor AP-1 activates the expression of numerous genes in response to mitogenic stimuli. AP-1 regulates gene expression both through solitary binding to independent recognition sites and, in cooperation with various heterologous transcription factors, through targeting to composite response elements. The two subunits that make up the AP-1 heterodimer, Fos and Jun, p...

Microorganisms growing in natural habitats are constantly confronted with a wide variety of external stresses. Here we provide several lines of experimental evidence for the thesis that the filamentous fungus Aspergillus nidulans has a homolog of the AP-1-like bZip transcription factor, which is known to play general roles in oxidative responses in many types of yeast.

We report the development of chimeric DNA binding peptides comprising a DNA binding fragment of natural transcription factors (the basic region of a bZIP protein or a monomeric zinc finger module) and an AT-Hook peptide motif. The resulting peptide conjugates display high DNA affinity and excellent sequence selectivity. Furthermore, the AT-Hook motif also favors the cell internalization of the ...

Many cellular processes in living organisms are regulated by complex regulatory networks, built from noncovalent interactions between relatively few proteins that perform their functions switching homo- and heterooligomeric assemblies or mono- bivalent states. Herein, we demonstrate the conjugation of a 4,4'-bipyridinium scaffold to basic region GCN4 bZip transcription factor can be exploited c...

The neurosteroid pregnenolone sulfate activates a signaling cascade in insulinoma cells involving activation of extracellular signal-regulated protein kinase and enhanced expression of the transcription factor Egr-1. Here, we show that pregnenolone sulfate stimulation leads to a significant elevation of activator protein-1 (AP-1) activity in insulinoma cells. Expression of the basic region leuc...

Epstein-Barr virus (EBV) reactivation from latency is known to be sensitive to redox regulation. The immediate-early protein Zta is a member of the basic-leucine zipper (bZIP) family of DNA binding proteins that stimulates viral and cellular transcription and nucleates a replication complex at the viral lytic origin. Zta shares with several members of the bZIP family a conserved cysteine residu...